<?php
class AWSOAuth {
	private static $SECRET_KEY = "+vB6pF3kIVHOljYeUnjIpziVHcJxy7F9j+fW3eWH";
	private static $ACCESS_KEY = "AKIAJHK7XI7GFCS24S2Q";

	private static $WRITE_SECRET_KEY = "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";
	private static $WRITE_ACCESS_KEY = "AKIAJXBZQQGTOWROMJPA";

	private STATIC $MINUTES_EXPIRES = 240;

	private function lazySignature($key, $data) {
		if (strlen($key) > 64) {
			$key = pack('H*', sha1($key));	
		}
		$key = str_pad($key, 64, chr(0x00));
		$ipad = str_repeat(chr(0x36), 64);
		$opad = str_repeat(chr(0x5c), 64);
		$hmac = pack( 'H*', sha1(
			($key ^ $opad) . pack( 'H*', sha1(
				($key ^ $ipad) . $data
				))
			));
		return base64_encode($hmac);
	}

	public function getFileSecureParams($bucket, $fileName) {
		$expires = time() + intval(floatval(AWSOAuth::$MINUTES_EXPIRES) * 60);
		$fileName = str_replace('%2F', '/', rawurlencode($fileName = ltrim($fileName, '/')));
		$signpath = '/'. $bucket .'/'. $fileName;
		$signsz = implode("\n", $pieces = array('GET', null, null, $expires, $signpath));
		$signature = $this->lazySignature(AWSOAuth::$SECRET_KEY, $signsz);

		$qs = http_build_query($pieces = array(
			'AWSAccessKeyId' => AWSOAuth::$ACCESS_KEY,
			'Expires' => $expires,
			'Signature' => $signature,
			));
		return $qs;
	}

	public function putFileSecureParams($bucket, $region, $filePath, $params = "") {
		$returnParams = array();

		$cleanFilePath = str_replace("%2F", "/", rawurlencode($filePath));
		$returnParams['clean_file'] = $cleanFilePath;
		$url = "https://".$bucket.".s3.amazonaws.com". $cleanFilePath . $params;
		$returnParams["url"] = $url;

		$now = time();
		$longDate = gmdate("Ymd\THis\Z", $now);
		$shortDate = gmdate("Ymd", $now);
		$method = "PUT";
		$service = "s3";
		$algorithm = "AWS4-HMAC-SHA256";
		$timeToLive = 3600;
		$contentHash = "UNSIGNED-PAYLOAD";

		$scope = $shortDate. "/" . $region . "/".$service."/aws4_request";
		$credentialString = AWSOAuth::$WRITE_ACCESS_KEY . "/" . $scope;

		$headers = array();
		$headers["host"] = parse_url($url, PHP_URL_HOST);
		$headers["x-amz-content-sha256"] = $contentHash;
		$headers["x-amz-date"] = $longDate;
		ksort($headers);

		$signedHeaders = implode(";", array_keys($headers));

		$query = parse_url($url, PHP_URL_QUERY);
		parse_str($query, $params);
		ksort($params);
		$query = http_build_query($params);
	    
	    $canonicalRequest = $this->generateCanonicalRequest($headers, $method, $cleanFilePath, $query, $signedHeaders, $contentHash);
		$returnParams["canonical_request"] = $canonicalRequest;

		$stringToSign = $this->generateStringToSign($canonicalRequest, $algorithm, $longDate, $scope);
		$returnParams["string_to_sign"] = $stringToSign;

		$signature = $this->generateSignature(AWSOAuth::$WRITE_SECRET_KEY, $shortDate, $region, $service, $stringToSign);
		$returnParams["signature"] = $signature;
		
		$authorizationString = $this->generateAuthorization($credentialString, $signedHeaders, $signature, $algorithm);

		$headers["Authorization"] = $authorizationString;
		unset($headers['host']);
		$returnParams["headers"] = $headers;

		return $returnParams;
	}

	public function getFileSecureParams2($bucket, $region, $filePath, $params = "") {
		$returnParams = array();
		$cleanFilePath = str_replace("%2F", "/", rawurlencode($filePath));
		$returnParams['clean_file'] = $cleanFilePath;
		$url = "https://".$bucket.".s3.amazonaws.com" . $cleanFilePath . $params;
		$returnParams["url"] = $url;

		$now = time();
		$longDate = gmdate("Ymd\THis\Z", $now);
		$shortDate = gmdate("Ymd", $now);
		$method = "GET";
		$service = "s3";
		$algorithm = "AWS4-HMAC-SHA256";
		$timeToLive = 3600;
		$contentHash = hash('sha256', '');

		$scope = $shortDate. "/" . $region . "/".$service."/aws4_request";
		$credentialString = AWSOAuth::$ACCESS_KEY . "/" . $scope;

		$headers = array();
		$headers["host"] = parse_url($url, PHP_URL_HOST);
		$headers["x-amz-content-sha256"] = $contentHash;
		$headers["x-amz-date"] = $longDate;
		ksort($headers);

		$signedHeaders = implode(";", array_keys($headers));

		$query = parse_url($url, PHP_URL_QUERY);
		parse_str($query, $params);
		ksort($params);
		$query = http_build_query($params);

		$canonicalRequest = $this->generateCanonicalRequest($headers, $method, $cleanFilePath, $query, $signedHeaders, $contentHash);
		$returnParams["canonical_request"] = $canonicalRequest;

		$stringToSign = $this->generateStringToSign($canonicalRequest, $algorithm, $longDate, $scope);
		$returnParams["string_to_sign"] = $stringToSign;

		$signature = $this->generateSignature(AWSOAuth::$SECRET_KEY, $shortDate, $region, $service, $stringToSign);
		$returnParams["signature"] = $signature;
		
		$authorizationString = $this->generateAuthorization($credentialString, $signedHeaders, $signature, $algorithm);

		$headers["Authorization"] = $authorizationString;		
		$returnParams["authorization"] = $authorizationString;
		unset($headers['host']);
		$returnParams["headers"] = $headers;

		return $returnParams;
	}

	public function generateAuthorization($credentialString, $signedHeaders, $signature, $algorithm) {
		$params = array();
		$params[] = "Credential=".$credentialString;
		$params[] = "SignedHeaders=" . $signedHeaders;
		$params[] = "Signature=" . $signature;
		return $algorithm . " " . implode(",", $params);
	}

	public function generateSignature($secretKey, $shortDate, $region, $service, $stringToSign) {
		$dateKey = hash_hmac("sha256", $shortDate, "AWS4" . $secretKey, true);
		$regionKey = hash_hmac("sha256", $region, $dateKey, true);
		$serviceKey = hash_hmac("sha256", $service, $regionKey, true);
		$signingKey = hash_hmac("sha256", "aws4_request", $serviceKey, true);
		return hash_hmac("sha256", $stringToSign, $signingKey);
	}

	public function generateStringToSign($canonicalRequest, $algorithm, $longDate, $scope) {
		$reqHash = hash("sha256", $canonicalRequest);
		
		$stringToSignData = array();
		$stringToSignData[] = $algorithm;
		$stringToSignData[] = $longDate;
		$stringToSignData[] = $scope;
		$stringToSignData[] = $reqHash;
		return implode("\n", $stringToSignData);
	}

	public function generateCanonicalRequest($headers, $method, $filePath, $query, $signedHeaders, $contentHash) {
		$canonicalHeaderData = array();
		foreach ($headers as $key => $value) {
			$canonicalHeaderData[] = $key . ":" . $value;
		}
		$canonicalHeaderString = implode("\n", $canonicalHeaderData);

		$canonicalRequestData = array();
		$canonicalRequestData[] = $method;
		$canonicalRequestData[] = $filePath;
		$canonicalRequestData[] = $query;
		$canonicalRequestData[] = $canonicalHeaderString;
		$canonicalRequestData[] = null;
		$canonicalRequestData[] = $signedHeaders;
		$canonicalRequestData[] = $contentHash;

		return implode("\n", $canonicalRequestData);
	}
}